White House spokeswoman Sarah Sanders said Trump and Guaido agreed to maintain regular communication after Venezuelan authorities opened an investigation that could lead to Guaido's arrest.
President Nicolas Maduro quickly shot back, cutting off diplomatic relations with Washington and accusing the USA of orchestrating a coup against his government.
The country's pro-government top court has barred Guaido, who is calling for large anti-Maduro street protests this week, from leaving the country.
"I am ready to sit down at the negotiating table with the opposition so that we could talk for the good of Venezuela", said Maduro, 56.
But given the failure of previous rounds of dialogue between the government and opposition, including one led by the Vatican, opponents are suspicious, believing Maduro uses them to quell protests and buy time.
The anti-Maduro protests on Wednesday were far smaller than the massive outpouring over the weekend, and the government repression in recent days may have discouraged a broader attendance.
That loyalty - fueled in part by regime-subsidized food allowances and bonuses - has provided core support in a string of election victories for Maduro's party, despite opposition boycotts and vote-rigging accusations.
She didn't want to say if she was against Maduro or what she thought about Guaido.
Maduro won a second six-year term last year in elections that the domestic opposition and many foreign countries have dismissed as rigged.
On Tuesday, Maduro announced he would beef up the nation's defense by expanding Venezuela's civilian armed militia to 2 million members amid escalating tensions with the U.S.
"Any violence and intimidation against US diplomatic personnel, Venezuela's democratic leader, Juan Guaido, or the National Assembly itself would represent a grave assault on the rule of law and will be met with a significant response".
In an early morning tweet, Mr Trump warned USA citizens against travelling to Venezuela, given the unrest. The two countries have a long history of ties and Maduro's predecessor Hugo Chavez, known for his tirades against the U.S., was a welcome guest at the Kremlin.
Venezuela's socialist President Nicolas Maduro warned the White House of "another Vietnam" this week; accusing the Trump administration of organizing a "coup d'etat" in the once-rich Latin American nation.
Venezuela's under-pressure President Nicolás Maduro has warned the U.S. indirectly of a military Intervention in the South American country: "we are not a Vietnam in Latin America", he said in a "the American people", addressed a video message, which was posted on Facebook. Guaido is being targeted by Venezuelan Supreme Court.
A group of soldiers rose up against Maduro last week and Venezuela's military attache to Washington deserted the president on Saturday, but for now, the military high command remains loyal to Maduro.
US President Donald Trump has spoken in support of Juan Guaido.
Abrams vowed that the United States would keep stepping up pressure on Maduro, a leftist firebrand who presides over a crumbling economy that has sent millions fleeing.